Small watercraft

ABSTRACT

An improved fuel delivery and injection system for a small watercraft engine reduces the heat effects within an enclosed engine compartment upon various components of the engine and upon the fuel within the fuel system. The fuel system integrates a fuel pump within a fuel tank at a location which minimizes the effects of watercraft leaning. The inlet of the fuel pump desirably corresponds, in the lateral direction, with a position of an inlet to the jet pump unit. In this position, the pump is less likely to draw air as the watercraft maneuvers. The fuel lines also are arranged within the engine to minimize the effect of engine heat produced by the exhaust system on the fuel delivery lines. The arrangement of the fuel pump and fuel delivery lines consequently improves the consistency of the fuel/air ratio within the fuel charge produced by the engine as less air and vapor delivered to the fuel injectors.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates in general to watercrafts, and inparticular to the adaptation of a small watercraft with an engine thatincludes a fuel delivery and injection system.

[0003] 2. Description of Related Art

[0004] Personal watercrafts have become popular in recent years. Thistype of watercraft is sporting in nature; it turns swiftly, is easilymaneuverable, and accelerates quickly. Personal watercraft todaycommonly carrier one rider and one or two passengers.

[0005] A relatively small hull of the personal watercraft define's anengine compartnent below a rider's area. An internal combustion enginefrequently lies within the engine compartment in front of a tunnelformed on the underside of the watercraft hull. The internal combustionengine commonly powers a jet propulsion device located within thetunnel. An impeller shaft commonly extends between the engine and thepropulsion device for this purpose.

[0006] Personal watercrafts often employ an in-line, multi-cylinder,crankcase compression, two-cycle engine. The engine conventionally lieswithin the engine compartment with the in-line cylinders aligned along alongitudinal axis of the watercraft hull (in the bow to sterndirection).

[0007] A dedicated carburetor usually supplies fuel to each cylinder ofthe engine.

[0008] Because of the sporting nature of the watercraft and the tendencyfor frequent, abrupt directional changes of the watercraft when used,prior personal watercraft engine employ floatless-type carburetors. Afuel system used with the floatless-type carburetors continuouslysupplies fuel from a fuel tank to the carburetors while returning excessfuel to the fuel tank.

[0009] Though floatless carburetors improve fuel delivery to theengine's intake, prior fuel supply systems have not been so immune toabrupt directional changes. The fuel pick-up port in the fuel tank oftenis exposed to air when the watercraft leans in a turn, especially whenthe fuel level within the tank is low. Air in the fuel line produces anumber of adverse affects. The fuel/air ratio of the charge delivered tothe engine cylinders is reduced which results in poor engineperformance. Air in the fuel line also can destroy the fuel pump'sprime, as well as cause some fuel pumps to run hotter and damage thepump either immediately or over time (i.e., reduce the pump'sdurability).

[0010] Carburetored engines also tend to produce a fuel charge of a lessthan accurate fuel/air ratio. Consequently, engine performance is notoptimized under all running conditions and greater pollutants canresult.

SUMMARY OF THE INVENTION

[0011] The present watercraft includes a fuel injection engine in orderto improve the accuracy of the fuel/air ratio of charge delivered to theengine cylinders, as well as reduce pollutants. The adaptation of a fuelinjected engine into the small watercraft raises some formidablechanges, however, such as, for example, eliminating air intake in thefuel supply system, as well as reducing the heat exposure of the fuelsupply and injection system.

[0012] Thus, in accordance with one aspect of the present invention,there is provided a small watercraft having a hull defining a rider'sarea. The rider's area is positioned behind a bow of the hull and issized to accommodate at least one rider. An internal combustion engineis located within the hull and drives a propulsion device that iscarried by the hull. A fuel supply system includes a fuel tank thatcommunicates with a fuel supply loop extending between the tank and theengine. A fuel pump is positioned within the fuel supply loop tocirculate fuel through the supply loop and is located within the fueltank.

[0013] Another aspect of the present invention involves a smallwatercraft having a hull defining a rider's area. The rider's area ispositioned behind a bow of the hull and is sized to accommodate at leastone rider. An internal combustion engine is located within the hull anddrives a propulsion device carried by the hull. An exhaust pipe isconnected to the engine. A fuel supply system includes a fuel deliveryline and a fuel return line that together define a fuel loop between theengine and a fuel tank. The fuel delivery line communicates with aplurality of fuel injectors of the engine. The fuel delivery and returnlines are arranged within the hull of the watercraft such that not morethan one of the lines extends next to any portion of the exhaust pipe.

[0014] In accordance with an additional aspect of the present invention,a small watercraft has a hull defining a rider's area. The rider's areais located behind a bow of the hull and is sized to accommodate at leastone rider. The hull has a longitudinal axis and defines an enginecompartment. A fuel-injected, internal combustion, multicylinder engineis located within the hull engine compartment and drives a propulsiondevice carried by the hull. The engine has a plurality of fuel injectorsto cyclically product a fuel charge within each cylinder of the engine.And a plurality of spark plugs of the engine ignite the fuel chargewithin the engine cylinders. An electronic control unit communicateswith the fuel injectors to control injection timing and volume. Theelectronic control unit also operates at least one ignition coil, whichis connected to at least one of the spark plugs, to control spark timingof the engine. In order to reduce interference noise, the electroniccontrol unit is mounted to the hull at a remote location relative to theignition coil.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] These and other features of the invention will now be describedwith reference to the drawings of preferred embodiments which areintended to illustrate and not to limit the invention, and in which:

[0016]FIG. 1 is a side elevational view of a personal watercraftconfigured in accordance with a preferred embodiment of the presentinvention;

[0017]FIG. 2 is a partial side sectional view of the personal watercraftof FIG. 1 illustrating an engine with a fuel supply and injectionsystem;

[0018]FIG. 3 is a schematic layout of the engine and fuel supply andinjection system of FIG. 2 together with an associated control system;

[0019]FIG. 4 is a partial top plan view of the engine of FIG. 2illustrating an oxygen sensor used with the engine;

[0020]FIG. 5 is a sectional top plan view of the watercraft of FIG. 2illustrating the arrangement of the watercraft's components within ahull of the watercraft;

[0021]FIG. 6 is a simplified top plan view of the watercraft of FIG. 4illustrating only select components within the watercraft hull;

[0022]FIG. 7 is a front sectional view of the watercraft of FIG. 2illustrating the position of a fuel pump inlet relative to a gulletinlet for a propulsion system of the watercraft;

[0023]FIG. 8 is a front sectional view of the watercraft, similar to theview illustrated in FIG. 6, but with the watercraft leaned to its portside;

[0024]FIG. 9 is a side sectional view of the watercraft of FIG. 2, butwith an another arrangement of the fuel supply and injection system;

[0025]FIG. 10 is a front elevational view of an embodiment of the engineand fuel supply and injection system of FIG. 2 with the watercraft hullshown in outline;

[0026]FIG. 11 is a front elevational view of an another embodiment ofthe engine and fuel supply and injection system of FIG. 2 with thewatercraft hull shown in outline;

[0027]FIG. 12 is a front elevational view of a further embodiment of theengine and fuel supply and injection system of FIG. 2 with thewatercraft hull shown in outline;

[0028]FIG. 13 is an upper plan view of the engine of FIG. 12 as view inthe direction of arrow A; and

[0029]FIG. 14 is a front elevational view of an additional embodiment ofthe engine and fuel supply and injection system of FIG. 2 with thewatercraft hull shown in outline.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0030]FIGS. 1 through 8 illustrate a personal watercraft 10 whichincludes a fuel supply system configured and arranged in accordance witha preferred embodiment of the present invention. Although the presentfuel supply system is illustrated in connection with an engine for apersonal watercraft, the fuel supply system can be used with other typesof watercraft as well, such as, for example, but without limitation,small jet boats and the like.

[0031] Before describing the fuel supply system, an exemplary personalwatercraft 10 will first be described in general details to assist thereader's understanding of the environment of use, the preferredarrangement of the fuel supply system within the watercraft 10, and theoperation of the fuel supply system. The watercraft 10 includes a hull12 formed by a lower hull section 14 and an upper deck section 16. Thehull sections 14, 16 are formed from a suitable material such as, forexample, a molded fiberglass reinforced resin. The lower hull section 14and the upper deck section 16 are fixed to each other around theperipheral edges in any suitable manner.

[0032] As viewed in the direction from the bow to the stem of thewatercraft, the upper deck section 16 includes a bow portion 18, acontrol mast 20 and a rider's area 22. The bow portion 18 slopesupwardly toward the control mast 20 and includes at least one air duct24 through which air can enter the hull. A cover 26 extends above anupper end of the air duct 24 to inhibit an influx of water into thehull.

[0033] The control mast 20 extends upward from the bow portion 18 andsupports a handlebar assembly 28. The handlebar 28 controls the steeringof the watercraft 10 in a conventional manner. The handlebar assembly 28also carries a variety of controls of the watercraft 10, such as, forexample, a throttle control, a start switch and a lanyard switch.

[0034] The rider's area 22 lies behind the control mast 20 and includesa seat assembly 30. In the illustrated embodiment, as best seen in FIGS.1 and 2, the seat assembly 30 has a longitudinally extendingstraddle-type shape which may be straddled by an operator and by atleast one or two passengers. The seat assembly 30, at least in principalpart, is formed by a seat cushion 32 supported by a raised pedestal 34.The raised pedestal 34 has an elongated shape and extends longitudinallyalong the center of the watercraft 10. The seat cushion 32 desirably isremovably attached to a top surface 36 of the pedestal 34 and covers theentire upper end of the pedestal for rider and passenger comfort.

[0035] An access opening 38 is located on an upper surface 36 of thepedestal 34. The access opening 38 opens into an engine compartmentformed within the hull. The seat cushion 32 normally covers and sealsclosed the access opening 38. When the seat cushion 32 is removed, theengine compartment is accessible through the access opening 38.

[0036] The pedestal 34 also includes a rear air duct 40 located behindthe access opening 38. The air duct 40 communicates with the atmospherethrough a space S between the pedestal 34 and the cushion 32 which isformed behind the access opening 38. Air passes through the rear duct 40in both directions, as schematically illustrated in FIG. 1.

[0037] As seen in FIG. 1, the upper deck section 16 of the hull 12advantageously includes a pair of raised gunnels 41 positioned onopposite sides of the aft end of the upper deck assembly 16. The raisedgunnels 41 define a pair of foot areas 43 that extend generallylongitudinally and parallel to the sides of the pedestal 34. In thisposition, the operator and any passengers sitting on the seat assembly30 can place their feet in the foot areas 43 with the raised gunnels 41shielding the feet and lower legs of the riders. A non-slip (e.g.,rubber) mat desirably covers the foot areas to provide increased gripand traction for the operator and the passengers.

[0038] The lower hull portion 14 principally defines the enginecompartment C. Except for the air ducts 24, 40, the engine compartment Cis normally substantially sealed so as to enclose an engine and the fuelsystem of the watercraft 10 from the body of water in which thewatercraft is operated.

[0039] With reference to FIG. 3, the lower hull 14 is designed such thatthe watercraft 10 planes or rides on a minimum surface area of the aftend of the lower hull 14 in order to optimize the speed and handling ofthe watercraft 10 when up on plane. FIG. 3 illustrates the water surfacelevel W₁ when the watercraft 10 is planing. For this purpose, the lowerhull section generally has a V-shaped configuration formed by a pair ofinclined section that extend outwardly from the keel line to outerchines at a dead rise angle. The inclined sections extend longitudinallyfrom the bow toward the transom of the lower hull 14 and is seen in FIG.4, extend outwardly to side walls of the lower hull. The side walls aregenerally flat and straight near the stem of the lower hull and smoothlyblend towards the longitudinal center of the watercraft at the bow. Thelines of intersection between the inclined section and the correspondingside wall form the outer chines of the lower hull section.

[0040] As seen in FIGS. 2 and 3, toward the transom of the watercraft,the inclined sections of the lower hull extend outwardly from a recessedchannel or tunnel 42 that extends upward toward the upper deck portion16. The tunnel 42 has a generally parallelepiped shape and opens throughthe rear of the transom of the watercraft 10, as seen in FIG. 1.

[0041] In the illustrated embodiment, a jet pump unit 44 propels thewatercraft. The jet pump unit 44 is mounted within the tunnel 42 formedon the underside of the lower hull section 16 by a plurality of bolt 46.An intake duct 48 of the jet pump unit 44 defines an inlet opening 50that opens into a gullet 52. The inlet opening 50 is defined at least inpart between a pair of side edges 51 The inlet opening 50 generally liesat or slightly below the water level W₁ when the watercraft is planing,as illustrated in FIG. 3.

[0042] The gullet 52 leads to an impeller housing 54 in which theimpeller of the jet pump 44 operates. An impeller duct assembly 56,which acts as a pressurization chamber, delivers the water flow from theimpeller housing to a discharge nozzle housing 58.

[0043] A steering nozzle 60 is supported at the downstream end of thedischarge nozzle 58 by a pair of vertically extending pivot pins. In anexemplary embodiment, the steering nozzle 60 has an integral lever onone side that is coupled to the handlebar assembly 28 through, forexample, a bowden-wire actuator, as known in the art. In this manner,the operator of the watercraft can move the steering nozzle 58 to effectdirectional changes of the watercraft 10.

[0044] A ride plate 62 covers a portion of the tunnel 42 behind theinlet opening 50 to enclose the pump chambers 54, 56 and the nozzleassembly 58 within the tunnel 42. In this manner, the lower opening ofthe tunnel 42 is closed to provide a planing surface for the watercraft.

[0045] An impeller shaft 64 supports the impeller within the impellerhousing 54. The aft end of the impeller shaft 64is suitable supportedand journalled within the compression chamber 56 in a known manner. Theimpeller shaft 64 extends in the forward direction through a front wallof the tunnel 42. A protective casing surrounds a portion the impellershaft 64 that lies forward of the intake gullet 52. In the illustratedembodiment, the protective casing has a tubular shape and is integrallyformed with the intake duct 48.

[0046] An internal combustion engine 66 of the watercraft powers theimpeller shaft 64 to drive the impeller of the jet pump unit 44. Theengine 66 is positioned within the engine compartment and is mountedprimarily beneath the control mast 20. Vibrationabsorbing engine mounts68 secure the engine 66 to the lower hull portion 14 in a known manner.The engine 66 is mounted in approximately a central position in thewatercraft 10.

[0047] In the illustrated embodiment, as best seen in FIGS. 2, 4 and 5,the engine 66 includes two in-line cylinders 67 and operates on atwo-stroke, crankcase compression principle. The engine 66 is positionedsuch that the row of cylinders lies parallel to a longitudinal axis ofthe watercraft 10, running from bow to stem. This engine type, however,is merely exemplary. Those skilled in the art will readily appreciatethat the present fuel delivery system can be used with any of a varietyof engine types having other number of cylinders, having other cylinderarrangements and operating on other combustion principles (e.g.,four-stroke principle).

[0048] As best seen in FIGS. 4 and 5, a cylinder block 70 and a cylinderhead assembly 72 desirably form the cylinders of the engine. A piston 74reciprocates within each cylinder of the engine 66 and together thepistons 74 drive an output shaft 76, such as a crankshaft, in a knownmanner. A connecting rod 78 links the corresponding piston 74 to thecrankshaft 76. The corresponding cylinder bore, piston and cylinder headof each cylinder forms a variable-volume chamber, which at a minimumvolume defines a combustion chamber of the cylinder 67. The cylinderhead supports a plurality of spark plug 79. The spark plugs 79 arepositioned to locate a gap of one spark plug 79 within each combustionchamber to ignite a fuel charge, as described below.

[0049] The crankshaft 76 desirably is journalled with a crankcase, whichin the illustrated embodiment is formed between a crankcase member 80and a lower end of the cylinder block 70. Individual crankcase chambers82 of the engine are formed within the crankcase by dividing walls andsealing disks, and are sealed from one another with each crankcasechamber communicating with a dedicated variable-volume chamber. Eachcrankcase chamber 82 also communicates with a charge former of aninduction system 84 (which is described below in detail) through a checkvalve (e.g., a reed-type valve). Because the internal details of theengine 66 desirably are conventional, a further description of theengine construction is not believed necessary to understand and practicethe invention.

[0050] The output shaft 76 carries a flywheel assembly 86 on a front endof the shaft at a position forward of the row of cylinders. The flywheelassembly 86 includes a flywheel magneto which forms part of a sparktiming circuit, as described below. A cover 88 is attached to the frontend of the cylinder block 70 and cylinder head 72 to enclose theflywheel assembly 86.

[0051] As seen in FIG. 2, a coupling 90 interconnects the enginecrankshaft 76 to the impeller shaft 64. A bearing assembly 92, which issecured to the bulkhead, supports the impeller shaft 64 behind the shaftcoupling 90.

[0052] As seen in FIG. 1, the output shaft 76 drives a generator 94(e.g., an alternator) to produce electricity for the watercraft 10. Forthis purpose, the output shaft 76 carries a drive pulley 96 at aposition between the coupling 90 and a rear surface of the engine 66.Alternatively, an intermediate shaft can connect the output shaft to thecoupling and carry the drive pulley. The generator 94 is mounted to thecylinder head 72 and includes a pulley coupled to an input shaft of thegenerator 94. In the illustrated embodiment, the axes of the generatorinput shaft 76 and the engine output shaft lie in parallel, and thegenerator pulley lies within the same transverse plane as the drivepulley 76, and desirably lies directly above the drive pulley 76. A beltinterconnects together the drive pulley 96 and the generator pulley suchthat the drive pulley 96 drives the generator pulley, i.e., the pulleysrotate together.

[0053] With reference to FIGS. 1, 4 and 5, an exhaust system 98 isprovided to discharge exhaust byproducts from the engine 66 to theatmosphere and/or to the body of water in which the watercraft 10 isoperated. The exhaust system 98 includes an exhaust manifold 100 that isaffixed to the side of the cylinder block 70 and which receives exhaustgases from the variable-volume chambers through exhaust ports in awell-known manner.

[0054] An outlet end of the exhaust manifold 100 communicates with aC-shaped pipe section 101. The C-pipe 101 includes an inner tube thatcommunicates directly with the discharge end of the exhaust manifold100. An outer tube surrounds the inner tube to form a coolant jacketbetween the inner and outer tubes. Although not illustrated, the C-pipe101 includes an inlet port positioned near its inlet end. The inlet portcommunicates with a water jacket of the engine 66.

[0055] The outlet end of the C-pipe 101 communicates with an expansionchamber 102. In the illustrated embodiment, the expansion chamber 102has a tubular shape in which an expansion volume 104 is defined withinan annular, thick wall. Coolant jacket passages extend through theexpansion chamber wall and communicate with the coolant jacket of theC-pipe 101.

[0056] A flexible coupling connects the outlet end of the C-pipe to theinlet end of the expansion chamber 102. The flexible coupling also canincludes an outlet port which communicates with an internal coolantpassage within the flexible coupling. The coolant passage places thecoolant jacket and the coolant passages in communication.

[0057] The outlet end of the expansion chamber 102 is fixed to reducerpipe which tapers in diameter toward its outlet. The pipe has a dualshell construction formed by an inner shell which defines an exhaustflow passage. The expansion volume 104 communicates with this passage.

[0058] An outer shell is connected to the inner shell and defines acooling jacket about the inner shell. The coolant jacket passages of theexpansion chamber communicate with the coolant jacket of the pipe todischarge a portion of the coolant with the exhaust gases.

[0059] A catalyzer 106 can be disposed within the space defined at themating ends of the expansion chamber and the reducer pipe. For instance,the catalyzer 106 can include an annular shell supporting ahoneycomb-type catalyst bed. The catalyst bed is formed of a suitablecatalytic material such as that designed to treat and render harmlesshydrocarbons, carbon monoxide, and oxides of nitrogen. An annular flangesupports the annular shell generally at the center of the flow paththrough the expansion chamber volume. In this manner, all exhaust gasflow through the expansion chamber 102 passes through the catalyst bed.The annular flange can be held between outlet end of the expansionchamber and the inlet end of the reducer pipe.

[0060] The lower section of the reducer pipe includes a downwardlyturned portion that terminates at the discharge end. The inner shellstops short of the outer shell such that the water flow through thewater jacket merges with the exhaust gas flow through the exhaustpassage at the discharge end.

[0061] A flexible pipe 108 is connected to the discharge end of thereducer pipe and extends rearward along one side of the watercraft hulltunnel 42. The flexible conduit 108 connects to an inlet section of awater trap device 110. The water trap device 1 10 also lies within thewatercraft hull 12 on the same side of the tunnel 42.

[0062] The water trap device 110 has a sufficient volume to retain waterand to preclude the back flow of water to the expansion chamber 102 andthe engine 66.

[0063] Internal baffles within the water trap device 110 help controlwater flow through the exhaust system.

[0064] An exhaust pipe 112 extends from an outlet section of the watertrap device 110 and, as best seen in FIG. 6, wraps over the top of thetunnel 42 to a discharge end 114. The discharge end 114 desirably opensinto the tunnel 42 at an area that is close to or actually below thewater level with the watercraft 10 floating at rest on the body ofwater.

[0065] As seen in FIGS. 2, 4 and 5, the induction system 84 is locatedon a side of the engine 66 opposite of the exhaust system 98 andsupplies a fuel/air charge the variable-volume chambers. In theillustrated embodiment, the induction system 84 includes an air intakesilencer 116. The silencer 116 is located above the engine 66 andincludes a plenum chamber.

[0066] The plenum chamber of the silencer 116 communicates with aplurality of throttle devices 118. The engine 66 desirably includes anumber of throttle devices 118 equal in number to the number ofcylinders. In the illustrated embodiment, the throttle devices 118 arethrottle valves. A throttle shaft supports a butterfly-type valve plate120 within a throat 122 of the throttle valve 118.

[0067] Each throttle valve 118 communicates with an intake passage 124of an intake manifold 126. The manifold 126 is attached to the crankcasemember 80 and/or cylinder block 70 to place each intake passage 124 incommunication with one of the crankcase chambers 82. In the illustratedembodiment, the intake passage 124 desirably has an arcuate shape with aportion of the passage 124 extending generally transverse to arotational axis of the crankshaft 76 and to a longitudinal axis of thewatercraft 10. As a result, the throttle valve 118 and intake silencer116 are distanced from the cylinder block and cylinder head assemblies70, 72.

[0068] A check valve (e.g., a reed valve) is disposed within each intakepassage 124 at the junction between the intake manifold 126 and thecrankcase member 80. In the illustrated embodiment, a reed valveassembly 128 includes a pair of reed valves which open upon upwardmovement to the piston 74 to permit an influx of a fuel/air charge intothe corresponding crankcase camber 82 and close upon downward movementof the piston 74 to inhibit reverse air flow from the chamber 82 intothe intake manifold 126.

[0069] The engine 66 also desirably includes the same number of chargerformers as the number of cylinders. In the illustrated embodiment, thecharger formers are fuel injectors 132 which spray fuel into thecorresponding intake passage 124; however, the present fuel deliverysystem can be used with other types of charge formers and arrangementsof the charge formers within the engine (e.g., direct injection) aswell.

[0070] The fuel delivery system supplies fuel to the fuel injectors 132.The fuel delivery system includes a main fuel tank 134 located withinthe hull 12. In the illustrated embodiment, a plurality ofvibration-damping mounts 136 support the fuel tank 134 at a position infront of the engine 66. Any of a variety of known means, such as, forexample, straps, can be used to secure the fuel tank 134 to the lowerhull portion 14 in this position.

[0071] A fuel filler hose 138 extends between a filler cap assembly 140and the fuel tank 134. In the illustrated embodiment, the filler capassembly 140 is secured to the bow portion 18 of the hull upper deck 16to the side and in front of the control mast 20. In this manner, thefuel tank 134 can be filled from outside the hull 12 with the fuelpassing through the fuel filler hose 138 into the fuel tank 134.

[0072] The fuel supply system also includes a high pressure fuel pump142 positioned within a fuel tank. In the illustrated embodiment, thefuel pump 142 is located within the main fuel tank 134; however, it isunderstood that the features of the present invention can be employedwith the fuel pump located within a sub-tank which receives fuel fromthe main fuel tank. For instance, many aspects of the present inventioncan be incorporated into a fuel system employing a vapor separator whichutilizes a sub-tank for vapor separator. Thus, the following descriptionof the main fuel tank is to be understood as applying equally toapplications involving a sub-tank.

[0073] The fuel tank 134 desirably includes a depression 144 in which aninfluent port of the fuel pump 142 is located. In the illustratedembodiment, the depression 144 is formed near the rear of the fuel tank134 on a bottom surface. Other locations of the depression, however,also are possible. The exemparly depression 134 includes a downwardlysloping front surface 146. The bottom of the depression 144 desirably issized to accommodate a fuel strainer 148 of the high pressure fuel pump142.

[0074] A fuel cock 149 closes a port 150 which is located at the bottomof the depression 144 on the rear side of the fuel tank 134. The fuelcock 149 provides a means for draining the fuel tank 134 in order toremove any spoiled fuel and water (especially salt water) that may haveentered the fuel system. The fuel cock 149 desirably is located belowthe influent port of the fuel pump 142 and below the strainer 148 inorder to drain these components and prevent rust formation.

[0075] The high pressure fuel pump 142 supplies fuel to the fuelinjectors 132 of the induction system 84. The fuel pump 142 draws fuelfrom the fuel tank 134 and pushes the fuel through a conduit 152 and afuel filter 154. After the filter 154, the fuel flows into a fuel railor manifold 156. The pump 142 delivers fuel under high pressure throughthe conduit 152 to the fuel rail 156. A check valve (not shown) isdisposed within the conduit 152 to prevent a back-flow of fuel from thefuel rod 156.

[0076] The fuel rail 156 has an elongated shape. An inlet port of thefuel rod 156 communicates with the conduit 152 which carries fuel fromthe high pressure pump 142. The inlet port opens into a manifold chamberwhich extends along the length of the fuel rod 156.

[0077] The fuel rail 156 delivers fuel to each fuel injector 132. Forthis purpose, the manifold chamber of the fuel rod 156 communicates withthe plurality of supply ports defmed along the length of the fuel rail156. Each supply port receives an inlet end of the corresponding fuelinjector 132 and communicates with an inlet port of the.fuel injector132 to supply the fuel injector 132 with fuel.

[0078] In the illustrated embodiment, the fuel rail 156 lies generallyparallel to the direction of travel of the watercraft 10, and also tothe longitudinal axis of the watercraft 10 and the rotational axis ofthe crankshaft 76. Fuel desirably flows through the fuel rail 156 in adirection from bow to stem in order to utilize the momentum of the fueltoward the watercraft's stem to increase the pressure within the fuelrail 156. As a result, a smaller size high pressure pump 142 can beused. The fuel can flow in the opposite direction, i.e., stem to bow, asillustrated in FIG. 10, but this would require a larger size pump. (FIG.10 illustrates the arrangement of the fuel delivery system to produce afuel flow through the fuel rail 156 in this reverse direction).

[0079] A fuel return line 158 extends between an outlet port of the fuelrail 156 and the fuel bowl 152 of the vapor separator 144. The returnline 156 completes the flow loop defmed by the high pressure side of thefuel supply system to generally maintain a constant flow of fluidthrough the fuel rail 156. The constant fuel flow through the highpressure side of the fuel delivery system inhibits heat transfer to thefuel and thus reduces fuel vaporization in the fuel rail 156.

[0080] A pressure regulator 160 is positioned within the return line158. The pressure regulator 160 generally maintains a desired fuelpressure at the injectors (e.g., 50-100 atm). The regulator 160regulates pressure by dumping excess fuel back to the fuel tank 134, asknown in the art.

[0081] A control system manages the operation of the engine 66. Thecontrol system includes an electronic control unit (ECU) 162 thatreceives signals from various sensors regarding a variety of enginefunctions. As schematically illustrated in FIG. 4, a crankcase positionsensor 164 senses the angular position of the crankshaft 76 and also thespeed of its rotation. The sensor 164 produces a signal(s) which isindicative of angular orientation and speed. Another sensor 166determines the throttle orientation to determine the opening degree ofthe throttle valves 118. The sensor 166 produces a signal indicative ofthe throttle valve position.

[0082] The ECU 162 receives these signals from the sensors 164, 166 tocontrol injection timing and duration, as well as spark timing. For thispurpose, the ECU 162 communicates with each fuel injector 132, andspecifically the solenoid 168 used with each fuel injector 132. The ECU162 controls the operation of the solenoid 168 in order to manage fuelinjection timing and duration, the latter affecting the fuel/air ratioof the produced charge. The desired stoichiometric fuel/air ratio willdepend upon the amount of air flow into the engine 66, which is afunction of the opening degree of the throttle valve 120. Thisinformation is stored within a memory device with which the ECU 162communicates. The ECU 162 thus processes the information signal receivedfrom the throttle valve sensor 166 and determines the amount of fuel tobe injected for the sensed operating condition of the engine. The ECU162 also uses the information from the crankshaft sensor 164 todetermine the point during the engine's revolution to initiate fuelinjection.

[0083] In addition to controlling fuel injection, the ECU 162 alsocontrol ignition timing. For this purpose the ECU controls a capacitordischarge ignition unit 170, and the firing of the spark plugs 79. Thegenerator 94 powers one or more charging coil (schematically illustratedas part of the capacitor discharge ignition unit) which increases thevoltage of the charge eventually delivered to the spark plugs 79. Thegenerator 79 also charges one or more batteries 172, as known in theart, as well as powers the fuel pump 142..

[0084] The capacitor discharge unit 170 desirably controls the dischargeof one ignition coil for each spark plug 79. The capacitor dischargeignition unit 170 receives a signal from the ECU 162 which manages thedischarge timing.

[0085] The engine management system also can include a feedback controlsystem. For this purpose, the engine 66 includes an oxygen sensor 174.As seen in FIG. 7, the oxygen sensor 174 has is sensing portion 176mounted within a collection chamber 178. The collection chamber 178communicates with at least one of the cylinders through an exhaust gaspassage 180, formed either in the cylinder block 70 or the cylinder head72. The oxygen sensor 174 desirably is mounted either on the front orthe rear surface of the engine 66, or on a side of the engine 66opposite of the side on which the induction system 84 and the exhaustsystem 98 are attached.

[0086] The oxygen sensor 174 produces and sends a signal to the ECU 162which is indicative of the oxygen content in the exhaust gases. Basedupon this information, the ECU 162 adjusts the fuel/air ratio, as knownin the art.

[0087] The arrangement of the components of the engine 66, enginecontrol system, fuel supply system and exhaust system are bestillustrated in FIGS. 2, 3, 6, 8 and 10. The fuel pump 142 desirably islocated so as to minimize the amount of air and/or fuel vapor drawn intothe pump 142 as the watercraft 10 is maneuvered through the water,especially during low fuel conditions. As seen in FIG. 3, the inlet ofthe fuel pump 142 and the fuel strainer 148 are positioned to liebetween the a pair of vertical extension planes V in which the sideedges 51 of the gullet inlet opening 50 lie. The fuel pump inlet andfuel strainer 148 desirably lies along the longitudinal center plane Lof the watercraft. The deliver pipe 152 also extend in a directiongenerally parallel to a vertical center plane L. In this position, thepump 142 draws less air than at other location within the fuel tank 134.

[0088] For instance, even under low fuel condition, with a fuel levelF₁, the pump inlet and fuel strainer 148 lie below the fuel level F₁ inthe tank 134. This is the condition illustrated in FIG. 3. And when thewatercraft is leaned to one side, the pump inlet and fuel strainer 148remain submerged within the fuel. This would not be the case, however,if the strainer 148 were located in an off center position, outside thevertical extension planes V, as illustrated in phantom in FIG. 10. Thepump 142 under these conditions would draw air and fuel vapors into thefuel line because the strainer 148 would lie above the fuel level F₂.The central position of the fuel pump 142 thus inhibits vapor influxinto the fuel delivery line 152 and fuel rail 156, even when the fuellevel in the tank 134 is low.

[0089] As best seen in FIG. 6, the fuel pump 142 desirably lies in frontof the engine 66 and between the air ducts 24, 40. In this position, theair flow between the ducts cools the fuel and the fuel pump 14. As aresult, the fuel pump 152 runs cooler and the durability and life-spanof the pump 152 tends to increase.

[0090] In the illustrated embodiment, the air ducts 24, 40 arepositioned to lie on a longitudinal center line L of the watercraft hull10. The output shaft 76 of the engine 66, as well as the row ofcylinders also lie on the longitudinal center line L for watercraftbalance.

[0091] As seen in FIG. 3, the position of the front air duct 24 can lieeither forward or reward of the main fuel tank 134. For ventilationpurposes, however, the air duct 24 desirably lies in front of the fueltank 134.

[0092] As seen in FIGS. 1 and 3, the battery 172 and the ECU 162desirably lie beneath the access opening 38 for easy access by atechnician. In this location, the battery 172 also lies within the airstream between the air ducts 24, 40 for ventilation purposes. In thealternative, the watercraft 10 can include two batteries 172 which arelocated on opposite sides of the watercraft center line L for goodbalance with the access opening 38 positioned between the batteries 172for easy access.

[0093] As seen in FIG. 8, the ECU 162 desirably is remotely locatedrelative to the charging coil 170. In one position, the ECU 162 islocated behind the engine 66 and beneath the access opening 38 and theseat 32, while the charging coil 170 and its enclosure 180 are locatedin front and to the side of the engine 66. Alternatively, the ECU 162 islocated on a side of the watercraft center line L opposite of thecharging coil 170 and enclosure 180. In this position the access opening38 is located between the ECU 162 and charging coil 170. Either of theselocation reduce signal noise experienced by the ECU 162 which thehigh-voltage charging coil tends to produce. In both of these positions,the ECU 162 also lies between the air ducts 24, 40, within the producedair cross-stream, which cools the ECU 162.

[0094]FIGS. 11 through 14 illustrate various arrangement of the fuelsupply system within the engine compartment, as well as several engineconfigurations which help isolate the fuel lines from the heat damage.Because of the similarity of components between the followingembodiments and the above-described embodiment, like reference numeralsare used to ease the reader's understanding.

[0095]FIG. 11 illustrates an engine 66 which is configured in accordancewith the above description. In this embodiment, the fuel system isarranged such that both the fuel rail 156 and the return line 160 arepositioned within the space between the throttle devices 118 and thecylinder block 70, above the transverse section of the intake passages126. In this position, the fuel lines 156, 160 lie within the air flowstream between the ducts 24, 40 and the air stream into the intakesilencer 116. The air flow over the fuel lines 156, 160 cools the fueland reduces indecencies of fuel vaporization within the lines 156, 160.

[0096]FIG. 12 and 13 illustrate an alternative engine arrangement inwhich the cylinders 67 are inclined to one side of the longitudinalcenter plane L. The engine 66 however, desirably is arranged within theengine compartment so that its output shaft 76 rotates about an axisthat lies within the plane L. The intake passages 126 lies on a side ofthe central plane L opposite of the cylinders 67. An exhaust pipe 186 ofthe exhaust system 98 is connected to a side of the cylinder block 70closest to the central plane L. As best seen in FIG. 13, the exhaustpipe 186 wraps around the front of the cylinder block 70 and thenextends along the lower side of the cylinders 67 toward the water trapdevice 110, which is positioned behind the engine 66.

[0097] The fuel rail 156 and the fuel injectors 132 are arranged betweenthe induction system 84 and the cylinder block 70, near the centralplane L. In the illustrated embodiment, the fuel rail 156 and the fuelinjectors 132 lie partially below the exhaust pipe 186 with the fuelinjectors 132 communicating with the intake passages 124 of the intakemanifold 126. It is understood, however, that the fuel injectors 132could alternatively be arranged to inject fuel directly into thecombustion chambers of the cylinders 67 or into scavenge passages of thecylinders 67, while lying within the valley formed between the inductionsystem 84 and the cylinder block 70.

[0098] In the illustrated embodiment, the fuel return line 160 extendson an opposite side of the induction system 84 from the side on whichthe exhaust pipe 186 is located. In this position, the return line 160lies away from the heat emitted by the exhaust pipe 186; however, thereturn line 160 also lies generally outside of the air stream betweenthe ducts 24, 40, as well as the air stream into the intake silencer116.

[0099]FIG. 14 illustrates an engine configured similarly to thatdescribed in connection with FIGS. 12 and 13. In this embodiment, thefuel rail 156 and the fuel return line 160 are arranged to lie on a sideof the intake passages 124 opposite of the side on which the exhaustpipe 186 lies. In this position, the fuel lines 156, 160 are remotelylocated relative to the exhaust pipe 186 in order to remove the lines156, 160 from the heat effects produced by the exhaust pipe 186.

[0100] As common with all of the embodiments described above, the fueldelivery system is arranged in the engine compartment in a mannerreducing the heat effects on the fuel lines, on the fuel within theline, and on the fuel pump. As a result, the consistency of the fuel/airratio of the produced fuel charge is increased as less fuel is vaporizedwithin the lines, and the durability of the fuel pump is improved.

[0101] Although this invention has been described in terms of certainpreferred embodiments, other embodiments apparent to those of ordinaryskill in the art are also within the scope of this invention.Accordingly, the scope of the invention is intended to be defined onlyby the claims that follow.

What is claimed is:
 1. A small watercraft having a hull defining arider's area behind a bow of the hull which is sized to accommodate atleast one rider, an internal combustion engine located within the hulland driving a propulsion device which is carried by the hull, and a fuelsupply system including a fuel tank communicating with a fuel supplyloop which extends between the engine, and a fuel pump positioned withinthe fuel supply loop to circulate fuel through the supply loop, the fuelpump being located within the fuel tank.
 2. A small watercraft as inclaim 1, wherein the fuel tank is located in front of the engine, towardthe bow of the hull.
 3. A small watercraft as in claim 1, wherein thefuel pump includes an inlet port positioned in a depression formed inthe fuel tank.
 4. A small watercraft as in claim 3, wherein saiddepression is located at the bottom of the fuel tank.
 5. A smallwatercraft as in claim 4, wherein said depression slopes downward to therear of the fuel tank.
 6. A small watercraft as in claim 1 additionallycomprising a fuel filler hose communicating with the fuel tank and witha fuel cap assembly located on an exterior surface of the watercrafthull.
 7. A small watercraft as in claim 1, wherein said hull defines atunnel on the underside of the hull, and the propulsion device is jetpump unit mounted in the tunnel, the jet pump unit including an intakeduct with an water inlet opening defined between a port side edge and astarboard side edge, and the fuel pump being located in front of thetunnel and between a pair of extension lines that project from the sidesof the water inlet opening.
 8. A small watercraft as in claim 1, whereinthe fuel tank includes a drain plug, and the inlet to the fuel pump islocated above the drain plug.
 9. A small watercraft as in claim 1additionally comprising first and second air ducts formed in the hull,and an inlet to the fuel pump being located within the hull at aposition between the air ducts.
 10. A small watercraft as in claim 1,wherein the engine includes a magneto-flywheel assembly and said fuelpump is located in front of the magnetoflywheel assembly.
 11. A smallwatercraft as in claim 1, wherein said fuel pump includes an electricmotor located within the fuel tank.
 12. A small watercraft as in claim11 additionally comprising a pair of batteries, the batteries beinglocated on opposites of a longitudinal center line of the hull, and atleast one of the batteries being in electrical connection with the motorof the fuel pump.
 13. A small watercraft as in claim 11, wherein theengine includes an alternator which supplies electricity to the motor ofthe fuel pump.
 14. A small watercraft as in claim 13, wherein an outputshaft of the engine drives the alternator through a drive mechanism, andthe drive mechanism is coupled to the output shaft at a point between arear surface of the engine and a coupling that interconnects the outputshaft to an impeller shaft of the propulsion device.
 15. A smallwatercraft as in claim 1, wherein the fuel loop of said fuel supplysystem includes a fuel rod that communicates with a plurality of fuelinjectors of the engine, and the fuel rod is positioned to lie generallyparallel to a rotational axis of an output shaft of the engine.
 16. Asmall watercraft as in claim 15, wherein the fuel pump is arranged inthe fuel supply loop to produce a flow of fuel through the fuel rod in adirection toward an aft end of the watercraft hull.
 17. A smallwatercraft having a hull defining a rider's area behind a bow of thehull which is sized to accommodate at least one rider, an internalcombustion engine located within the hull and driving a propulsiondevice which is carried by the hull, an exhaust pipe connected to theengine, and a fuel supply system including a fuel delivery line and afuel return line that together define a fuel loop between the engine anda fuel tank, the fuel delivery line communicating with a plurality offuel injectors, said fuel delivery and return lines being arrangedwithin the hull of the watercraft such that not more than one of saidlines extends next to any portion of the exhaust pipe.
 18. A smallwatercraft as in claim 17 additionally comprising a fuel filler hoseextending between the fuel tank and a fuel cap assembly located on anexterior surface of the watercraft hull.
 19. A small watercraft as inclaim 17, wherein a portion of said fuel delivery line extends next to aportion of the exhaust pipe.
 20. A small watercraft as in claim 17,wherein said engine includes an output shaft which rotates about an axisin a crankcase of the engine, the crankcase is divided into a pluralityof crankcase chambers, and an induction system of the enginecommunicates with each crankcase chamber and is located to one side of avertical plane that passes through the axis of the output shaft.
 21. Asmall watercraft as in claim 20, wherein at least a portion of theinduction system extends in a direction away from the vertical plane.22. A small watercraft as in claim 21, wherein the induction system liesbetween the vertical plane and the fuel delivery line.
 23. A smallwatercraft as in claim 21, wherein the fuel delivery line lies in aspace between the vertical plane and the induction system.
 24. A smallwatercraft as in claim 23, wherein the exhaust pipe lies on a side ofthe vertical plane opposite of the fuel delivery line.
 25. A smallwatercraft as in claim 20, wherein the engine includes a plurality ofinclined cylinders, and each cylinder is leaned to a side of thevertical plane opposite the side on which the induction system lies. 26.A small watercraft as in claim 25, wherein the fuel delivery line liesbetween the inclined cylinders and the induction system.
 27. A smallwatercraft as in claim 26, wherein a portion of the exhaust pipe lieswithin the space between the inclined cylinders and the inductionsystem, and the fuel delivery line lies within a space defmed betweenthe induction system, the portion of the exhaust pipe and the inclinedcylinders.
 28. A small watercraft as in claim 25, wherein the inductionsystem lies between the fuel delivery line and the inclined cylinders.29. A small watercraft as in claim 20, wherein the induction system liesbetween the fuel return line and the vertical plane.
 30. A smallwatercraft as in claim 17 additionally comprising an oxygen sensorcommunicating with at least one cylinder of the engine.
 31. A smallwatercraft as in claim 30, wherein a sensor end of the oxygen sensor ismounted in a collection chamber which communicates with at least one ofthe cylinders of the engine through a collection passage.
 32. A smallwatercraft as in 30, wherein the induction system and the exhaust pipeare each connected to one of the sides of a cylinder block assembly ofthe engine and the oxygen sensor is connected to the cylinder blockassembly on either the front or rear ends of the cylinder blockassembly.
 33. A small watercraft as in claim 30, wherein the inductionsystem and exhaust pipe are connected to a cylinder block assembly onthe same side of the cylinder block assembly, and the oxygen sensor isconnected to the cylinder block assembly on any of the other sides andends of the cylinder block assembly.
 34. A small watercraft having ahull defining a rider's area behind a bow of the hull which is sized toaccommodate at least one rider, the hull having a longitudinal axis anddefining an engine compartment, a fuel-injected, internal combustion,multicylinder engine located within the hull engine compartment anddriving a propulsion device which is carried by the hull, the enginehaving a plurality of fuel injectors to produce a fuel charge within theengine cylinders, a plurality of spark plugs which ignite the fuelcharge within the engine cylinders, and an electronic control unit thatcommunicates with the fuel injectors to control injection timing andvolume and that operates an ignition coil, which is connected to thespark plugs, to control spark timing, the electronic control unit beingmounted to the hull at a remote location relative to the ignition coil.35. A small watercraft as in claim 34, wherein one of the electroniccontrol unit and the ignition coil lies toward a bow of the watercrafthull and the other of the electronic control unit and the ignition coillies toward a stem of the watercraft hull.
 36. A small watercraft as inclaim 34, wherein one of the electronic control unit and the ignitioncoil lies on one side of the hull longitudinal axis and the other one ofthe electronic control unit and the ignition coil lies on the other sideof the hull longitudinal axis.
 37. A small watercraft as in claim 34,wherein the riders area of the hull includes a seat having an accessopening into the engine compartment positioned beneath the seat, and theelectronic control unit being located within the engine compartment at aposition below the access opening.
 38. A small watercraft as in claim34, wherein the hull includes at least two air ducts that communicatewith the engine compartment, and the electronic control unit is locatedbetween the air ducts.
 39. A small watercraft having a hull defining arider's area behind a bow of the hull which is sized to accommodate atleast one rider, an internal combustion engine located within an enginecompartment formed within the hull and driving a propulsion device whichis carried by the hull, a pair of air ducts communicating with theengine compartment and located on opposite sides of the engine, anexhaust pipe connected to the engine, and a fuel supply system includinga fuel delivery line and a fuel return line that together define a fuelloop between the engine and a fuel tank, the fuel delivery linecommunicating with a plurality of fuel injectors, said fuel delivery andreturn lines being arranged within the hull of the watercraft such thatat least one of said lines extends between the air ducts.
 40. A smallwatercraft as in claim 39, wherein said engine includes an output shaftwhich rotates about an axis in a crankcase of the engine, the crankcaseis divided into a plurality of crankcase chambers, and an inductionsystem of the engine communicates with each crankcase chamber and islocated to one side of a vertical plane that passes through the axis ofthe output shaft.
 41. A small watercraft as in claim 39, wherein atleast a portion of the induction system extends in a direction away fromthe vertical plane.